JP6072762B2 - Non-aqueous electrolyte secondary battery positive electrode, method for producing the same, and non-aqueous electrolyte secondary battery - Google Patents

Description

  The present invention relates to a positive electrode for a non-aqueous electrolyte secondary battery, a method for producing the same, and a non-aqueous electrolyte secondary battery.

  Conventionally, non-aqueous electrolyte secondary batteries such as lithium secondary batteries have been widely used as power sources for electronic devices and the like.

  In recent years, it has been desired to increase the capacity of nonaqueous electrolyte secondary batteries. Examples of a method for increasing the capacity of the nonaqueous electrolyte secondary battery include a method for increasing the charging voltage. For example, when lithium cobaltate is used as the positive electrode active material of a non-aqueous electrolyte secondary battery, if the non-aqueous electrolyte secondary battery is charged to 4.3 V with respect to metallic lithium, the capacity of the non-aqueous electrolyte secondary battery is It becomes about 160 mAh / g. On the other hand, when the non-aqueous electrolyte secondary battery is charged to 4.5 V with respect to metallic lithium, the capacity of the non-aqueous electrolyte secondary battery is about 190 mAh / g.

  When the charging voltage of the nonaqueous electrolyte secondary battery is increased, there is a problem that the nonaqueous electrolyte is easily decomposed by the positive electrode active material. In particular, when a nonaqueous electrolyte secondary battery is charged at a high charge voltage at a high temperature, the nonaqueous electrolyte is more easily decomposed.

  Patent Document 1 includes an adhesion step of depositing a phosphate compound on composite oxide particles containing lithium and nickel, and a heating step of heat-treating the composite oxide particles deposited with the phosphate compound. A method for producing a positive electrode active material is disclosed. In Patent Document 1, it is proposed to increase the charging current capacity of a secondary battery by using a positive electrode active material obtained by such a manufacturing method.

JP 2010-55777 A

  When the secondary battery disclosed in Patent Document 1 is continuously charged at a high temperature, characteristics such as the charge / discharge efficiency, capacity retention rate, and discharge capacity retention rate of the secondary battery may deteriorate.

  In the present invention, even when the nonaqueous electrolyte secondary battery is continuously charged at a high temperature, characteristics such as the charge / discharge efficiency, capacity retention rate, discharge capacity retention rate, etc. of the nonaqueous electrolyte secondary battery are unlikely to deteriorate. The main object is to provide a positive electrode for a water electrolyte secondary battery.

The positive electrode for nonaqueous electrolyte secondary batteries according to the present invention includes a positive electrode active material layer. The positive electrode active material layer includes a positive electrode active material and a compound represented by the general formula (1): MH ₂ PO ₂ . In the general formula (1), M is a monovalent cation.

  The nonaqueous electrolyte secondary battery of the present invention includes the positive electrode, the negative electrode, a nonaqueous electrolyte, and a separator.

The method for producing a positive electrode for a non-aqueous electrolyte secondary battery according to the present invention is for forming a positive electrode active material layer by mixing a compound represented by the general formula (1): MH ₂ PO ₂ , a positive electrode active material, and a solvent. A step of obtaining a slurry, and a step of applying a slurry for forming a positive electrode active material layer on a positive electrode current collector and drying to form a positive electrode active material layer. In the general formula (1), M is a monovalent cation.

  According to the present invention, even when the nonaqueous electrolyte secondary battery is continuously charged at a high temperature, characteristics such as the charge / discharge efficiency, capacity retention rate, and discharge capacity retention rate of the nonaqueous electrolyte secondary battery are unlikely to deteriorate. A positive electrode for a non-aqueous electrolyte secondary battery can be provided.

1 is a schematic cross-sectional view of a nonaqueous electrolyte secondary battery in an embodiment of the present invention. It is a schematic sectional drawing of the positive electrode for nonaqueous electrolyte secondary batteries in one Embodiment of this invention. It is a graph showing the alternating current impedance characteristic of the battery A and the batteries C-E.

  Hereinafter, an example of the preferable form which implemented this invention is demonstrated. However, the following embodiment is merely an example. The present invention is not limited to the following embodiments. The drawings referred to in the embodiments are schematically described, and the ratio of the dimensions of the objects drawn in the drawings may be different from the ratio of the dimensions of the actual objects. The specific dimensional ratio of the object should be determined in consideration of the following description.

  As shown in FIG. 1, the nonaqueous electrolyte secondary battery 1 includes a battery container 17. In the present embodiment, the battery container 17 has a flat shape. However, in the present invention, the shape of the battery container is not limited to a flat shape. The shape of the battery container may be, for example, a cylindrical shape or a square shape.

  An electrode body 10 impregnated with a nonaqueous electrolyte is accommodated in the battery container 17.

  As the non-aqueous electrolyte, for example, a known non-aqueous electrolyte can be used. The non-aqueous electrolyte includes a solute, a non-aqueous solvent, and the like.

As the solute of the non-aqueous electrolyte, for example, LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (SO ₂ F) ₂ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiC _{(SO 2 CF 3) 3,} LiC (SO 2 C 2 F 5) 3, LiClO ₄ or the like can be mentioned. The non-aqueous electrolyte may contain one type of solute or may contain a plurality of types of solutes.

  Examples of the non-aqueous solvent for the non-aqueous electrolyte include cyclic carbonates, chain carbonates, mixed solvents of cyclic carbonates and chain carbonates, and the like. Specific examples of the cyclic carbonate include ethylene carbonate, fluoroethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, vinyl ethylene carbonate, and the like. Specific examples of the chain carbonate include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate and the like. As a non-aqueous solvent having a low viscosity and a low melting point and a high lithium ion conductivity, a mixed solvent of a cyclic carbonate and a chain carbonate is preferably used. In the mixed solvent of cyclic carbonate and chain carbonate, the mixing ratio of cyclic carbonate and chain carbonate (cyclic carbonate: chain carbonate) may be in the range of 1: 9 to 5: 5 by volume ratio. preferable.

  The nonaqueous electrolyte may be a gel polymer electrolyte in which a polymer electrolyte such as polyethylene oxide or polyacrylonitrile is impregnated with an electrolytic solution.

  The electrode body 10 is formed by winding a negative electrode 11, a positive electrode 12, and a separator 13 disposed between the negative electrode 11 and the positive electrode 12.

  The separator 13 can suppress a short circuit due to contact between the negative electrode 11 and the positive electrode 12 and is impregnated with a nonaqueous electrolyte. Separator 13 can be constituted by a porous film made of resin, for example. Specific examples of the resin porous membrane include a polypropylene porous membrane and a polyethylene porous membrane, and a laminate of a polypropylene porous membrane and a polyethylene porous membrane.

  The negative electrode 11 includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector. The negative electrode current collector can be formed of a foil made of a metal such as Cu or an alloy containing a metal such as Cu, for example.

  The negative electrode active material layer includes a negative electrode active material. The negative electrode active material is not particularly limited as long as it can reversibly store and release lithium. Examples of the negative electrode active material include carbon materials such as graphite and coke, metal oxides such as tin oxide, metals that can be alloyed with lithium such as silicon and tin, and lithium, metal lithium, and the like. Among these, a carbon material is preferable as a negative electrode active material because it has little volume change associated with insertion and extraction of lithium and is excellent in reversibility.

  The negative electrode active material layer may contain a carbon conductive agent such as graphite, a binder such as sodium carboxymethyl cellulose (CMC) and styrene butadiene rubber (SBR).

  As shown in FIG. 2, the positive electrode 12 includes a positive electrode current collector 12a and a positive electrode active material layer 12b disposed on the positive electrode current collector 12a. The positive electrode current collector 12a can be formed of a foil made of a metal such as Al or an alloy containing a metal such as Al, for example.

  The positive electrode active material layer 12b includes a positive electrode active material. The positive electrode active material layer 12b may contain a binder, a conductive agent, and the like in addition to the positive electrode active material. Specific examples of the binder include polytetrafluoroethylene and polyvinylidene fluoride (PVDF). Specific examples of the conductive agent include carbon materials such as graphite, acetylene black, and carbon black. The positive electrode active material may be in the form of particles.

The kind of positive electrode active material is not particularly limited. The positive electrode active material is composed of, for example, a lithium-containing transition metal oxide. The lithium-containing transition metal oxide preferably has a layered structure. Examples of the lithium-containing transition metal oxide include a lithium-nickel composite oxide, a lithium-nickel-cobalt-aluminum composite oxide, a lithium-nickel-cobalt-manganese composite oxide, and a lithium-cobalt composite oxide. Etc. Lithium cobaltate in which at least one of Al and Mg is solid-solved inside the crystal and Zr is fixed to the surface is preferable as a lithium-containing transition metal oxide because of its high crystal structure stability. When the lithium-containing transition metal oxide contains nickel, the proportion of nickel in the lithium-containing transition metal oxide is preferably 40 mol% or more from the viewpoint of reducing the amount of cobalt used. The positive electrode active material may be composed of only one type or may be composed of two or more types.

The positive electrode active material layer 12b has the following general formula (1):
MH ₂ PO ₂ (1)
[Wherein M is a monovalent cation. ]
The compound (1) represented by these is included. In the compound (1), M is preferably at least one selected from the group consisting of NH ₄ , Na, Li and K, and more preferably at least one of NH ₄ and Na.

  The compound (1) is considered to function as a reducing agent in the positive electrode active material layer 12b of the nonaqueous electrolyte secondary battery 1. That is, it is considered that the oxidation and decomposition of the nonaqueous electrolyte are suppressed by oxidizing the compound (1) in the positive electrode active material layer 12b. When the decomposition of the nonaqueous electrolyte is suppressed, the amount of gas generated in the nonaqueous electrolyte secondary battery 1 is reduced, and characteristics such as capacity retention rate and charge / discharge efficiency are hardly deteriorated.

  In addition, when a positive electrode active material layer forming slurry is applied onto the positive electrode current collector 12a and dried in the positive electrode manufacturing process described later, a part of the compound (1) is a transition metal in the positive electrode active material. It is thought that it reduces. For this reason, the electroconductivity of the positive electrode active material surface is improved, and the discharge capacity maintenance rate of the nonaqueous electrolyte secondary battery 1 is increased.

  The positive electrode 12 can be manufactured as follows, for example. First, the positive electrode active material, the compound (1), and a solvent are mixed to obtain a positive electrode active material layer forming slurry. As the solvent, N-methyl-2-pyrrolidone (NMP) or the like is preferably used. The positive electrode active material layer forming slurry may be mixed with a conductive agent, a binder, and the like. The order of mixing the positive electrode active material, the compound (1), the solvent, the conductive agent, the binder and the like is not particularly limited. In addition, compound (1) may be mixed as a solid or as an aqueous solution. An aqueous solution containing the compound (1) may be sprayed on the positive electrode active material.

  Next, the positive electrode active material layer forming slurry is applied onto the positive electrode current collector 12a and dried to form the positive electrode active material layer 12b. Through the above steps, the positive electrode 12 can be completed.

  In Patent Document 1, the phosphate compound is decomposed by heat-treating the composite oxide particles to which the phosphate compound is applied. Compound (1) decomposes when heated at a temperature of about 200 ° C. or higher. However, in the nonaqueous electrolyte secondary battery 1, when the compound (1) is decomposed, the effect of the compound (1) as a reducing agent is lost, and the battery thickness may increase.

  In order not to thermally decompose the compound (1), the positive electrode active material layer forming slurry to which the compound (1) is added is preferably dried at a temperature of 150 ° C. or lower, and is dried at a temperature of 130 ° C. or lower. More preferred.

_{Incidentally, NaH 2 PO 2 · H 2} O and _{(NH 4) H 2 PO 2} , LiH 2 PO 2, KH 2 pyrolysis reaction scheme is believed to be caused by PO ₂ and overheat 200 ° C. or higher, the reaction formula (I) to (IV).

(I) 5NaH ₂ PO ₂ → Na ₄ P ₂ O ₇ + NaPO ₃ + 2PH ₃ + 2H ₂
(II) 7 (NH ₄ ) H ₂ PO ₂ → H ₂ P ₂ O ₇ + 2HPO ₃ + H ₂ O + 7NH ₃ + 2H ₂
(III) 5LiH ₂ PO ₂ → Li ₄ P ₂ O ₇ + LiPO ₃ + 2PH ₃ + 2H ₂
(IV) 5KH ₂ PO ₂ → K ₄ P ₂ O ₇ + KPO ₃ + 2PH ₃ + 2H ₂

  In the positive electrode active material layer 12b, the compound (1) is preferably contained in an amount of 0.001 part by mass or more, more preferably 0.02 part by mass or more, relative to 100 parts by mass of the positive electrode active material. More preferably, the content is 04 parts by mass or more. This is because if the content of the compound (1) is too small, the effect of improving the charge / discharge efficiency of the nonaqueous electrolyte secondary battery 1 may not be sufficiently obtained.

  In the positive electrode active material layer 12b, the compound (1) is preferably contained in an amount of 1.0 part by mass or less, more preferably 0.5 part by mass or less, relative to 100 parts by mass of the positive electrode active material. More preferably, 2 parts by mass or less is included. When there is too much content of a compound (1), the gas generation amount in the nonaqueous electrolyte secondary battery 1 will increase easily, and the thickness of the nonaqueous electrolyte secondary battery 1 may become large easily.

  Hereinafter, the present invention will be described in more detail based on specific examples. However, the present invention is not limited to the following examples, and can be appropriately modified and implemented without departing from the scope of the invention.

Example 1
A positive electrode active material, acetylene black, and polyvinylidene fluoride (PVDF) were kneaded together with NMP to prepare a slurry. As a positive electrode active material, LiCoO ₂ (Al and Mg are each dissolved in 1.0 mol% and 0.05 mol% of Zr adheres to the surface), LiNi _1/3 Co _1/3 A mixture of Mn _1/3 O _{2 at} a mass ratio of 9: 1 was used. The mass ratio of the positive electrode active material, acetylene black, and PVDF was set to 95: 2.5: 2.5. Next, as an additive, NaH ₂ PO ₂ .H ₂ O powder pulverized in a mortar and passed through a mesh having an opening of 20 μm was prepared. 0.1 parts by weight of this additive was added to 100 parts by weight of the positive electrode active material and stirred to prepare a slurry for forming a positive electrode active material layer. A slurry for forming a positive electrode active material layer was applied to both surfaces of an aluminum foil, dried at 120 ° C. for 3 minutes, and then rolled to obtain a positive electrode. The packing density of the positive electrode was 3.8 g / ml.

[Production of negative electrode]
Graphite, styrene-butadiene rubber, and carboxymethylcellulose were kneaded with water in a mass ratio of 98: 1: 1 to prepare a negative electrode mixture slurry. This negative electrode mixture slurry was applied to both sides of a copper foil, dried, and then rolled to obtain a negative electrode.

[Production of non-aqueous electrolyte]
Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed at a volume ratio of 3: 6: 1. Then, a mixture was obtained by adding LiPF ₆ so that the amount of LiPF ₆ is 1.0 mol / l. With respect to 100 parts by mass of this mixture, vinylene carbonate was added at a ratio of 2 parts by mass to obtain a nonaqueous electrolyte.

[Battery assembly]
Lead terminals were attached to the positive electrode and the negative electrode obtained above, respectively. Next, the positive electrode and the negative electrode facing each other through a separator were wound up in a spiral shape. The obtained wound body was crushed to obtain a flat electrode body. Next, the electrode body and the non-aqueous electrolyte were put in a battery container made of an aluminum laminate, and the battery container was sealed to prepare a battery A. The design capacity of the battery A was 800 mAh. The design capacity of the battery A was designed based on the end-of-charge voltage when the battery A was charged to a voltage of 4.4V. The size of the battery A was 3.6 mm × 35 mm × 62 mm.

  The battery A was charged with constant current at 0.5 It (400 mA) until the voltage reached 4.4V. Next, the battery A was charged to a current of 40 mA at a constant voltage of 4.4 V, and then left for 10 minutes. Next, constant current discharge was performed on the battery A at 0.5 It (400 mA) until the voltage reached 2.75 V.

[60 ° C continuous charge storage test]
Performed once charged and discharged at 1 It (800 mA) with respect to cell A, the discharge capacity was measured _{Q 0.} Next, the thickness of the battery A was measured. Next, the battery A was charged at a constant voltage of 4.4 V for 65 hours in a constant temperature bath at 60 ° C. Next, the thickness of the battery A was measured to determine the increase in battery thickness. Then, after cooling the battery A to room temperature, then discharged at 1 It (800 mA) at room temperature, to measure the discharge capacity _{Q 1.} The capacity retention rate (%) was calculated by the following formula (A).

Capacity retention ratio _{(%) = Q 1 / Q} 0 × 100 (A)

Next, the charged and discharged at 1 It (800 mA) with respect to cell A, to measure the charge capacity _{Q C} and the discharge capacity _{Q D.} The charge / discharge efficiency (%) after the continuous charge storage test was calculated by the following formula (B).

Discharge efficiency after continuous charge storage test _{(%) = Q D / Q} C × 100 (B)

[Discharge performance evaluation]
The battery A was charged with constant current at 0.5 It (400 mA) until the voltage reached 4.4V. Next, the battery A was charged to a current of 40 mA at a constant voltage of 4.4 V, and then left for 10 minutes. Next, constant current discharge was performed on the battery A at 1 It (800 mA) until the voltage reached 2.75 V, and the discharge capacity Q _{1 C} at _{1 It} was measured.

Next, the battery A was charged with a constant current at 0.5 It (400 mA) until the voltage reached 4.4V. Next, the battery A was charged to a current of 40 mA at a constant voltage of 4.4 V, and then left for 10 minutes. Next, constant current discharge was performed on the battery A at 3 It (2400 mA) until the voltage reached 2.75 V, and the discharge capacity Q _3C at _{3 It} was measured. The discharge capacity retention rate (%) was calculated by the following formula (C) to evaluate the discharge performance.

Discharge capacity maintenance rate (%) = Q _3C / Q _1C × 100 (C)

  As described above, each characteristic of the battery A was evaluated. The results are shown in Table 1.

(Example 2)
In the preparation of the positive electrode _in place of _{NaH 2 PO 2 · H 2 O} , except for using NH ₄ H ₂ PO 2 as an additive, to prepare a battery B in the same manner as the battery A, the characteristics of the battery B evaluated. The results are shown in Table 1.

(Comparative Example 1)
In the preparation of the positive electrode, except for not using the _{NaH 2 PO 2 · H 2 O} , to produce a cell C in the same manner as the battery A, and evaluated the characteristics of the battery C. The results are shown in Table 1.

(Comparative Example 2)
In the preparation of the positive electrode in place _{of NaH 2 PO 2 · H 2 O} , except for using NaH _{2 PO} 3 · 5H 2 O as an additive, to prepare a battery D in the same manner as the battery A, a battery D Characteristics were evaluated. The results are shown in Table 1.

(Comparative Example 3)
In the preparation of the positive electrode _in place of _{NaH 2 PO 2 · H 2 O} , except for using _NaH 2 PO ₄ as an additive, to prepare a battery E in the same manner as the battery A, and evaluated the characteristics of the battery E . The results are shown in Table 1.

(Comparative Example 4)
In the preparation of the positive electrode _in place of _{NaH 2 PO 2 · H 2 O} , except using of NH ₄ H 2 PO ₄ as an additive, to prepare a battery F in the same manner as the battery A, the characteristics of the battery F evaluated. The results are shown in Table 1.

(Comparative Example 5)
In the preparation of the positive electrode _in place of _{NaH 2 PO 2 · H 2 O} , except for using _Li 3 PO ₄ as an additive, to prepare a battery G in the same manner as the battery A, and evaluated the characteristics of the battery G . The results are shown in Table 1.

  As shown in Table 1, in battery A and battery B, the increase in battery thickness was smaller than in batteries C to G. From this result, it is understood that the battery A and the battery B generate less gas than the batteries C to G.

  In the batteries A and B, the capacity maintenance rate was higher than those of the batteries C to G. This is considered due to the fact that the gas generation amounts of the battery A and the battery B are suppressed as compared with those of the batteries C to G.

  The charge / discharge efficiencies of the battery A and the battery B were almost 100%. In Battery C to Battery G, the transition metal was eluted from the positive electrode, and deposited on the negative electrode to cause micro shorts. As a result, the charge / discharge efficiency was considered to be low.

[Measurement of AC impedance]
Before performing the 60 ° C. continuous charge storage test, the AC impedances of the battery A and the batteries C to E were measured under the following conditions. The results are shown in FIG. In the graph of FIG. 3, the horizontal axis is the real part of AC impedance, and the vertical axis is the imaginary part of AC impedance.

(Charging conditions)
The battery was charged with constant current at 1.0 It (800 mA) until the voltage reached 4.4V. Next, the battery was charged at a constant voltage of 4.4 V until 1/20 It (40 mA).

(AC impedance measurement conditions)
The AC impedance of the battery was measured by changing the frequency from 1 MHz to 30 MHz with an amplitude of 10 mV.

  As shown in FIG. 3, in the battery A to which the compound (1) represented by the general formula (1) was added, a reduction in AC impedance was observed. This is thought to be due to the improved conductivity of the positive electrode active material surface. This result also corresponds to the result in Table 1 that the discharge capacity maintenance rate of the battery A was improved as compared with those of the batteries C to G.

(Example 3)
In the preparation of the positive electrode, except that the added 0.02 parts by weight of _{NaH 2 PO} 2 · _H 2 O powder with respect to the positive electrode active material 100 parts by weight, to prepare a battery H in the same manner as the battery A, a battery H Characteristics were evaluated. The results are shown in Table 2.

Example 4
In the preparation of the positive electrode, except that the added 0.05 parts by mass of _{NaH 2 PO} 2 · _H 2 O powder with respect to the positive electrode active material 100 parts by weight, to prepare a battery I in the same manner as the battery A, a battery I Characteristics were evaluated. The results are shown in Table 2.

(Example 5)
In the preparation of the positive electrode, except that the added 0.2 parts by mass of _{NaH 2 PO} 2 · _H 2 O powder with respect to the positive electrode active material 100 parts by weight, to prepare a battery J in the same manner as the battery A, a battery J Characteristics were evaluated. The results are shown in Table 2.

  From the results shown in Table 2, it can be seen that when the content of the additive in the positive electrode active material layer decreases, the charge / discharge efficiency decreases, and when the content of the additive increases, the battery thickness increases.

(Example 6)
In the preparation of the positive _electrode, and the NaH _{2 PO} 2 · _H 2 O and an aqueous solution dissolved in water. Next, this aqueous solution was added dropwise to the positive electrode active material while stirring the positive electrode active material used in Battery A. NaH ₂ PO ₂ was adjusted so as to have a mixed amount of 0.1 parts by mass with respect to 100 parts by mass of the positive electrode active material. Then, what was dried at 120 degreeC for 2 hours was kneaded with acetylene black, polyvinylidene fluoride, and NMP, and it was set as the slurry for positive electrode active material layer formation. A battery K was produced in the same manner as the battery A, except that the positive electrode active material layer forming slurry thus obtained was used, and the characteristics of the battery K were evaluated. The results are shown in Table 3.

  From the results shown in Table 3, it can be seen that when producing the positive electrode, the characteristics of the battery can be improved by mixing the compound (1) represented by the general formula (1) in either a powder or an aqueous solution state. .

DESCRIPTION OF SYMBOLS 1 ... Nonaqueous electrolyte secondary battery 10 ... Electrode body 11 ... Negative electrode 12 ... Positive electrode 12a ... Positive electrode collector 12b ... Positive electrode active material layer 13 ... Separator 17 ... Battery container

Claims (6)

A positive electrode active material;
The following general formula (1):
MH ₂ PO ₂ (1)
[Wherein M is a monovalent cation. ]
A compound represented by
A positive electrode for a non-aqueous electrolyte secondary battery, comprising a positive electrode active material layer containing 2. The positive electrode for a nonaqueous electrolyte secondary battery according to claim 1, wherein in the compound represented by the general formula (1), M is at least one selected from the group consisting of NH ₄ , Na, Li and K. 3.   The non-aqueous electrolyte 2 according to claim 1 or 2, wherein the compound represented by the general formula (1) is contained in an amount of 0.001 parts by mass or more and 1.0 parts by mass or less with respect to 100 parts by mass of the positive electrode active material. Positive electrode for secondary battery.   A nonaqueous electrolyte secondary battery comprising the positive electrode for a nonaqueous electrolyte secondary battery according to claim 1, a negative electrode, a nonaqueous electrolyte, and a separator. The following general formula (1):
MH ₂ PO ₂ (1)
[Wherein M is a monovalent cation. ]
A step of mixing a compound represented by: a positive electrode active material and a solvent to obtain a positive electrode active material layer forming slurry;
Applying the positive electrode active material layer forming slurry onto the positive electrode current collector and drying to form a positive electrode active material layer;
A method for producing a positive electrode for a non-aqueous electrolyte secondary battery. The following general formula (1):
MH ₂ PO ₂ (1)
[Wherein M is a monovalent cation. ]
A step of dissolving a compound represented by:
Adding a solution in which the compound represented by the general formula (1) is dissolved to the positive electrode active material;
Mixing a positive electrode active material to which a solution in which the compound represented by the general formula (1) is dissolved and a solvent are mixed to obtain a positive electrode active material layer forming slurry;
Applying the positive electrode active material layer forming slurry onto the positive electrode current collector and drying to form a positive electrode active material layer;
A method for producing a positive electrode for a non-aqueous electrolyte secondary battery.